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United States Patent | 6,068,728 |
Xuan | May 30, 2000 |
The depth of focus of a lens focusing system for laser texturing a magnetic recording medium is increased by reversing the lens system. Lens reversal provides symmetrical energy distributions in both negative and positive defocus ranges. An embodiment includes a lens focusing system comprising a planoconvex lens, wherein the laser light beam is passed into the planar surface and out through the convex surface to impinge upon a substrate. Another embodiment includes a multiple lens focusing system comprising an aplanatic meniscus lens and a companion doublet, wherein the laser light beam is sequentially passed into a concave surface of the aplanatic meniscus lens and through the companion doublet lens.
Inventors: | Xuan; Jialuo Jack (Milpitas, CA) |
Assignee: | Seagate Technology, Inc. (Scotts Valley, CA) |
Appl. No.: | 919120 |
Filed: | August 28, 1997 |
Current U.S. Class: | 156/345.1; 118/50.1; 219/121.6; 219/121.75 |
Intern'l Class: | C23F 001/02 |
Field of Search: | 118/50.1 156/345 219/121.6,121.68,121.69,121.75 369/44.38 |
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